May 3, 2006 

Mr. David Staudt 

Center for Disease Control and Prevention 

Acquisition and Assistance Field Branch 

Post Office Box 18070 

626 Cochrans Mill Road – B-140 

Pittsburgh, PA 15236-0295 

Subject: Contract No. 200-2004-03805, Task Order 1: Transmittal of Attachment 6 

of the Draft Review of the NIOSH Site Profile for the Y-12 National Security Complex 

Dear Mr. Staudt: 

Enclosed is Attachment 6, Site Expert Review Summary, of the Draft Review of the NIOSH Site 

Profile for the Y-12 National Security Complex. This document was delivered to you on 

September 19, 2005; however, Attachment 6 was not included in that deliverable, as it had not 

yet been completed or subjected to the appropriate clearance for classified information. 

Please insert this Attachment in the appropriate place in your draft copy of SCA-TR-TASK1-

0007. Should you have any questions regarding this deliverable, please contact me at 732-530-

0104. 

Sincerely, 

John Mauro, PhD, CHP 

Project Manager 

cc: P. Ziemer, PhD, Board Chairperson 

Advisory Board Members 

L. Wade, PhD, NIOSH

L. Elliott, NIOSH 

J. Neton, PhD, NIOSH 

S. Hinnefeld, NIOSH 

L. Homoki-Titus, NIOSH 

A. Brand, NIOSH 

J. Broehm, NIOSH 

L. Shields, NIOSH 

A. Makhijani, PhD, SC&A 

H. Behling, SC&A 

M. Thorne, SC&A 

D. Chan, SC&A 

H. Chmelynski, SC&A 

J. Fitzgerald, Saliant 

J. Lipsztein, SC&A 

K. Robertson-DeMers, CHP, Saliant 

S. Ostrow, PhD, SC&A 

K. Behling. SC&A 

 Project File (ANIOS/001/07) 
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Attachment 6: Site Expert Review Summary 

Interviews were conducted with 35 BWX Technologies, Inc. (BWXT), production, maintenance, 

and health physics personnel, and 3 Wackenhut Services, Inc. (WSI), security guards, who are 

currently employed and have worked at the Y-12 National Security Complex in Oak Ridge, 

Tennessee, collectively since 1969. The interviews were conducted by Joseph Fitzgerald and 

Kathryn Robertson-DeMers, Q-cleared members of the SC&A Y-12 review team. The purpose 

of these interviews was to receive first-hand accounts of past radiological control and personnel 

monitoring practices at Y-12, and to better understand how operations were conducted. 

Production operations interviews were conducted by Mr. Fitzgerald in groups of 3–5 employees 

on June 14 and June 15, 2005. Interviewees were selected by worker representatives to represent 

a reasonable cross-section of production areas and job categories. Radiological control and 

security interviews were conducted by Ms. Robertson-DeMers on June 2–3, 2005. Three guards 

with long employment histories, including the union health and safety representative, were 

interviewed together. Field radiological control, dosimetry, and environmental monitoring 

personnel were interviewed in three sessions, respectively. Interviews were conducted onsite in 

secure meeting rooms at Y-12. Time was also spent reviewing classified and unclassified health 

physics records and reports, and conversing with records staff. 

Workers were briefed on the purpose of the interviews, and background on the Energy 

Employees Occupational Illness Compensation Program Act of 2000 (EEOICPA) dose 

reconstruction program and site profiles, and asked to provide their names in case there were 

follow-up questions. Union workers interviewed signed a visitor log. Participants were 

reminded that participation was strictly voluntary and that all interviewer notes would be 

reviewed for classification following the interview. 

Y-12 facilities represented by the site experts interviewed included Buildings 9201-2, 9201-5, 

9204, 9206, 9212, 9215, 9995, and 9998. The job categories represented included the following: 

• Steamfitter 

• Chemical Operator 

• Maintenance 

• Janitor 

• Machinist 

• “Outside” Machinist 

• Boilermaker 

• Electrician 

• Electroplater 

• Health Physics 

• Environmental Monitoring 

• Security Guards 

Individuals interviewed were given the opportunity to review the documented interview for 

accuracy and completeness. This is an important safeguard against missing key issues or 
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misinterpreting some vital piece of information. Some disagreement between site experts arose 

related to documented policies for radiation protection versus actual practice. Both views are 

presented in the summary. 

All interviews have been documented and summarized below. The information provided is not a 

verbatim discussion, but is a summary of information from multiple interviews with multiple 

individuals. Individuals have provided this information based on their personal experience. It is 

recognized that these former worker recollections and statements may need to be further 

substantiated before adoption in the Technical Basis Document (TBD). However, they stand as 

critical operational feedback. These interview notes are provided in that context; former worker 

input is similarly reflected in our discussion and, with the preceding qualifications in mind, has 

contributed to our findings and observations. 

Radiological Control (Rad Con) Organization 

The radiation protection group, throughout the operational history of the Y-12 Plant, was 

centralized. There have been centralized procedures applicable to all areas of the facility. In 

1969, the safety department at Y-12 included health physics, criticality safety, industrial hygiene, 

environmental monitoring, and some waste management activities. Technicians in the safety 

department performed health physics, industrial hygiene, and environmental monitoring duties. 

Industrial Hygiene separated from the Radiation Safety Department in the 1970s. Criticality 

Safety split off in 1988. The environmental monitoring group also eventually split from the 

Radiation Safety Department and became an independent group. In the 1970s, there were about 

30–40 individuals working for the Radiation Safety Department. This number increased to about 

135 in the 1980s and 175 in the 1990s. The Health Physics Department was subdivided and 

included a group referred to as Health Physics Services. This group was responsible for 

instrumentation, dosimetry, radiobioassay, and special projects. The Tennessee Department of 

Environment and Conservation (TDEC) has general oversight and a right to audit the Y-12 Plant. 

Radiation Protection Requirements 

The regulatory basis and/or guidance for the radiation protection program have varied over time. 

Initially, Y-1186, Health Physics Program, was issued in 1957. This document summarized the 

recommendations of National Council on Radiation Protection (NCRP) 59 issued in 1954, which 

were adopted later by the Atomic Energy Commission (AEC) in AEC Manual, Chapter 0550, 

Codes and Standards for Health, Safety, and Fire Protection. The Y-12 document was updated 

over the years to reflect the most current recommendations of the NCRP and the International 

Commission on Radiation Protection (ICRP). Subsequent radiation protection program 

documentation included the following: 

• 	 Y-KB-27, Radiation Safety and Industrial Hygiene – Guides and Limits (Issued 1970s). 

• 	 K/TL – 1074, Development of Derived Levels for Radiation Control (the Bailey Report) 

(Issued 1981). 
 

 

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• 	 DOE 5480.1A, Environmental Protection, Safety and Health Protection Program for DOE 

Operations, Chapter XI, “Requirements for Radiation Protection” (Issued August 1981). 

• 	 Y/DD-291, Oak Ridge Y-12 Plant Health Physics Handbook (Issued August 1984). 

• 	 DOE Order 5480.11, Radiation Protection for Occupational Workers (Issued December 

1988). Initially, the company had what was referred to as the Radiation Protection Standard, 

a company-level document based on national and international standards. 

From 1992–1996, the U.S. Department of Energy Radiological Control Manual provided 

program implementation guidance. Finally, in 1996, 10 CFR 835, Occupational Radiation 

Protection, became the regulatory requirement governing radiation protection programs across 

the DOE. 

Workforce 

Former Y-12 contractors include the Tennessee Eastman Corporation (1943–1947), the Union 

Carbide Company (1948–1984), Martin Marietta Energy Systems, Inc. (1984–1996), Lockheed 

Martin Energy Systems, Inc. (1996–2000), and BWXT Y-12 LLC (2000–present). The 

construction contractor at the site was MK Ferguson (formerly Rust Engineering). Up until 

approximately 1990, Y-12 provided health physics support to the construction contractor. From 

1990–1998, MK Ferguson developed its own Radiation Protection Program, and their health 

physics support was independent of the Y-12 Health Physics (HP) group. Y-12 provided their 

dosimetry and radiobioassay services. MK Ferguson had their own set of instruments, and was 

responsible for the calibration of those instruments. They also did their own dose calculations, 

based on raw data provided by Y-12. In 1998, Bechtel Jacobs came to the site to take over 

decontamination and decommissioning, and legacy waste operations. Although Bechtel Jacobs’s 

staff physically worked onsite, they contracted their health physics services to an outside 

organization (not Y-12 HP). 

On the Y-12 site, workers often moved between different operations. This was especially true of 

support personnel, such as health physics, security, crafts, and janitorial staff. Maintenance 

workers and janitors moved around the various facilities and operations on a frequent basis. 

These workers performed cleanup and maintenance work on all machines and processes. In 

some situations, a large building had its own maintenance support within the building. Unlike 

other employees, machinists and chemical operators were assigned to specific shops. 

The movement of the work force between Y-12 and the other Oak Ridge sites was common. 

Occasionally individuals from one plant were loaned to another site. Extended assignments to 

other facilities usually resulted in a change in employment. There was a Central Engineering 

staff, which was utilized by Y-12, Oak Ridge National Laboratory, and Oak Ridge Gaseous 

Diffusion Plant. 

Overtime hours were often significant, at times approaching 20 hours per week in certain job 

categories (e.g., chemical operators, trades, machinists). Building 9212, in particular, has a 

history of extensive overtime. There was a substantial amount of overtime in the guard force. 
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Security was working 60 or more hours per week from 1981 or 1982 through 1993. Although 

there was overtime prior to the 1980s, it increased during this heavy production era. In 1994, 

when the plant was shutdown, there was a reduction in force. As a result, security had to do the 

same work with fewer individuals. Therefore, from 1994–1996, security personnel were 

working up to 70 hours per week. This overtime was not optional. From 1997–2001, the work 

week decreased to about 60 hours per week. Following September 11, 2001, the average work 

week was 60–65 hours per week. 

Production 

Production was a priority over radiological control historically. Uranium was not considered a 

significant radiological hazard. Production goals were established and those goals were met! 

When serious safety problems were encountered, there was stop-work authority exercised by 

radiological control staff. The number of employees working at Y-12 was tied to production. At 

the end of the Cold War, large programs at Y-12 started to wind down. The DOE put the plant in 

standdown in September 1994 with influence from the Defense Nuclear Facility Safety Board. 

Many operations have restarted, but others are still shutdown. 

Oak Ridge National Laboratory (ORNL) maintained the Biology Building (9203), Fusion Project 

(9201-2), and post-Tennessee Eastman Corporation (TEC) Calutron Operations (9204-3) on the 

Y-12 site. Their technical support and radiation protection personnel were ORNL employees 

who worked at the Y-12 site. Y-12 radiation protection staff provided minimal support to these 

projects, such as source inventory and control. Y-12 personnel, such as maintenance, criticality 

safety, janitorial services, security, etc., supported ORNL projects and regularly cleaned or 

worked in these areas. These individuals had free access to the ORNL operations at Y-12. 

Other radionuclides processed or worked with at the Y-12 plant included 237Np, 238Pu, 239Pu,

240Pu, 228Th, 230Th, 232Th, and americium. Processing of 233U occurred on and off in Building 

9206. Tritium has been and is stored at Y-12. To the best of one site expert’s knowledge, there 

have not been any sources of 226Ra onsite, except a few radioactive sources. 

Recycled uranium was received at Y-12 starting in the late 1950s. Y-12 was getting metal and 

liquid products from Savannah River. Apparently, Y-12 managers wanted to keep Y-12 uranium 

production lines strictly segregated from these recycling operations. There was a concern over 

the presence of “sister” products in the recycled feed that would contaminate the uranium 

processes. 

When recycled uranium (RU) materials were received, the seal of incoming material was broken 

and a sample taken. The sample was analyzed to determine if feed material was within Y-12 

specifications related to impurities. The analysis evaluated 106Ru, 144Ce, 95Zr, transuranics, and 

other radionuclides concentrations. The ratio of impurities to uranium was tracked by Health 

Physics. Most transuranics present at Y-12 are in trace quantities as part of recycled uranium. 

Plutonium-239 and 241Am were on the order of parts per billion upon receipt. As the material 

went through the chemical processing, impurities, and uranium daughters were removed from the 
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product, but concentrated in the raffinate. As a result, the West End Treatment Facility is 

considered a transuranics area. 

Thorium was used at Y-12 to manufacture parts. There were heavy thorium campaigns in the 

1960s. The principal chemical form was thorium metal. Processing of thorium involved 

considerable rolling, shaping, and machining. Health Physics indicated that special precautions 

were used, including air sampling and machine enclosures. Machinists handling thorium 

indicated no special precautions were taken during the grinding and shaping of thorium metal. 

The presence of plutonium was denied by plant managers for many years. Plutonium was 

separated for the last time in Calutrons (9204-3) in 1978–1979. However, workers were told that 

recycled “tear downs” from Los Alamos needed to be checked for plutonium. Workers indicated 

that the Building 9203 facility contained plutonium. The “plutonium laboratory” remains 

contaminated (with sealed gloveboxes), is kept on negative pressure, and is kept locked. 

Historically, some parts or components were “sputtered” with plutonium. 

Security 

In general, the security force was rotated throughout the plant based on the post they were 

assigned to. This included providing security support to ORNL buildings on the Y-12 site. 

Security was responsible for a variety of functions at the Y-12 Plant. When material was 

transported between facilities in a “blue goose,” security was required to escort the material. 

Some Alarm Check tours took them into areas where they had to climb over and around 

containerized special nuclear material. They also were frequently around unassembled parts. 

They served as escorts for visitors and personnel as necessary. In addition, they were involved in 

the destruction of classified material at the Burnhouses. The exact content of the documents is 

unknown, as they were bagged. 

Buildings 9206 and 9212 were the most radioactively hazardous buildings onsite. Both housed 

incinerators. Building 9206 housed the heavy water and the green salt conversion process. 

Workers in Building 9206 would collect the ash from the incinerators wearing respiratory 

protection, while security wore nothing. Special Nuclear Material was stored in Building 9720-

5, production areas, and in other areas of the plant. Buildings 9720-9, 9720-10, and 9720-11 

were secured metal buildings. 

Some posts were located adjacent to the production area. Building 9215 was involved in 

machining and milling of highly enriched uranium. There was a control point (Post 50) in this 

area where individuals had to hand over their badge and get an area-specific badge. This post 

also served as a monitoring station for special nuclear material and metal coming in and out of 

the facility. There were also posts near the location where industrial x-rays were taken. The 

instruments at the post would peg when x-raying of casting was underway. 

Security personnel provided personnel frisking after Personnel Contamination Monitor alarms 

starting sounding in the late 1980s. Guards received minimal training (i.e., battery check, basic 

operation) on conducting these personnel surveys. They remember occasionally (a couple of 
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times per month) finding uranium chips on employees leaving the area. The chips would stick to 

the clothes. 

There was a vault located in Building 9213 where criticality experiments were conducted by 

scientists from ORNL for a period of time. This area was used for security training and storage 

of vests and equipment. The vault was posted as a contamination area, although they were told it 

was a fixed contamination area. Security conducted drills in and among equipment in the scrap 

yard, which also had fixed contamination. At times they would hide inside the equipment. 

Guards wore coveralls for work. Both their work and personal clothing were stored in the same 

locker. They also wore company-issued shoes. During escorting activities, there were situations 

where escorted individuals or other individuals in the area were provided with personal 

protective equipment (PPE), whereas security personnel were not. For example, if security was 

simply escorting workers performing a task that required a respirator, they may or may not be 

required to wear a respirator. 

Prior to Radiation Work Permits (RWPs), there was no routine bioassay monitoring for security 

personnel. Very few lung counts were done. Sampling or counts were performed following 

suspected incidents. When RWPs were implemented, the bioassay became RWP-based and 

anyone who entered under that RWP submitted the appropriate samples. 

External Dosimetry 

Line supervision had the responsibility for notifying Health Physics when employee work 

locations changed or new employees were hired. All employees were given film dosimeters 

from 1961 to 1980. From 1980 to the mid-1990s, all employees had a thermoluminescent 

dosimeter (TLD). In the mid-1990s, TLD issuance was reduced to include only those workers 

with a need to access radiological areas, including radioactive material areas. 

Currently, the RWP prescribes the dosimeter to be used. Additional information may also be 

available in the work planning documents. Special dosimetry may have been required in some 

situations. For example, the disassembly of the Department of Defense reactors (e.g., Fran 

reactor) required additional dosimetry and radiological controls. Typically, non-routine 

operations require work planning. The historic Health Physics reports indicate that special 

evaluations were done for select jobs. 

In 1947, Union Carbide Corporation became the contractor for ORNL, the Oak Ridge Gaseous 

Diffusion Plant (K-25), the Y-12 plant, and the Paducah Gaseous Diffusion Plant (Paducah). 

Processing of film badges for Union Carbide facilities was actually completed at Y-12. ORNL 

did have what they referred to as a “Radiation Worker dosimeter,” which was assembled and 

processed at ORNL. Each individual facility was responsible for dosimeter distribution. From 

the 1980s forward, the policy was that if you were on the Y-12 payroll, Y-12 was responsible for 

providing personnel monitoring. The switch from film badges to TLDs was a corporate decision 

that affected Y-12, K-25, and ORNL. Initially, the TLD was a two-chip dosimeter; however, in 

1989 a corporate decision was made to change to the four-chip dosimeter. 
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From 1949–1960, a small fraction of the population was monitored. These included individuals 

in Building 9212, chemical operators, machinists, and all other individuals working with 

radioactive material. Currently, there are approximately 2,500 radiological workers at Y-12. 

The total workforce is approximately 4,700. In the late 1980s/early 1990s, virtually everyone 

onsite received a film badge. Most of the construction workers were also monitored. 

Assignment of dosimeters to subcontract personnel and visitors was based on entry into a 

radiological area. In 1994, a dosimeter-needs assessment was performed. Eventually, external 

monitoring was discontinued for non-radiological workers. 

In the past, the photo identification and associated dosimeter was worn on the collar, because the 

security credential had to be visible. This was even the case in Building 9206 glovebox that had 

their maximum exposure at waist level. One worker (not an interviewee) was exposed at the 

waist level to a narrow beam of radiation from a gap in his glovebox shielding. Those working 

in arc melting were assigned two dosimeters; one badge worn at the collar above the lead apron 

and the other badge worn on the torso under the lead apron. The higher of the two results was 

recorded in the dose of record. At least as far back as the 1950s, workers took their routine 

dosimeter home at the end of their shift. 

Workers were later instructed to wear their dosimeter on their torso. Neutron dosimeters were to 

be worn on the belt or clipped to the shirt. Due to the potential for contamination, dosimeters 

were placed inside of a plastic baggie (“twirlie”) upon dressing out in coveralls for the radiation 

areas and taped to the front of the coverall. External dosimetry staff completed an analysis of the 

effect of this practice on the beta dose and determined the density thickness of the plastic was 

less than that of the coveralls (i.e., coveralls would provide beta shielding, if badge was worn 

under them.) 

Temporary badges were issued when the routine badge was forgotten in the earlier years. When 

the dosimeter was coupled with the security credential, individuals were sent home to get their 

badge. With those workers who had both a routine and temporary dosimeter, the results were 

summed and recorded as the dose of record. 

The original extremity dosimetry was crude and consisted of film attached to the hand with 

electricians tape. This type of monitoring began in the late 1940s. Chemical operators wore ring 

dosimeters when handling transuranics, particularly plutonium. 

There have been approximately 1%–2% lost or damaged dosimeters over the past 15 years. In 

conditions where dosimeters are lost or damaged, external dose is calculated based on survey 

data and time of exposure, previous monitoring data, and/or co-worker dose. This information is 

documented and included in the person’s Personnel Dosimetry Record (PDR) file. 

There have been no fading or other film badge response studies located by the External 

Dosimetry staff to date. The switch from film badges to TLDs occurred in 1980. There were 

performance data and comparison data on both the film and TLD programs. There were several 

studies completed related to the TLD response. From 1989 forward, angular response and 

linearity were tested and the relative impact to the dose evaluated. Fading studies were also 
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conducted, and correction factors were considered in the dose calculation algorithm. Quality 

assurance shots on the TLD system were/are periodically done. Data comparing pocket 

ionization chamber (PIC) results and the film badge results are available in the HP progress 

reports back as far as 1948. The plant used stay times; however, timekeeping was not used to the 

knowledge of the site experts. 

Neutron monitoring was assigned to individuals working around neutron generating sources and 

the 86” Cyclotron. In the 1980s and 1990s, workers in the UF4 processing (fluid beds) and 

storage areas were monitored for neutron exposure. No positive results were observed for these 

individuals, so the neutron monitoring for this group was discontinued in the mid- to late-1990s. 

The insensitive portion of the NTA film was evaluated to determine whether there was photon 

exposure detected. If the result from the insensitive film was below an established threshold 

(based on known neutron-to-photon ratios), the sensitive film was not processed. A zero value 

was recorded in this case. External dosimetry staff was not aware of a particular methodology 

used to determine slow neutron dose in the era when NTA film was used. Historically, 

beta/gamma dosimeter results less than the minimum detectable dose results were recorded as 

zero. Null values, which occur in some records, indicate that the dosimeter was not read. 

Currently, if an individual is not monitored (i.e., no dosimeter number), there is an absence of 

records in the dosimetry records 

The area dosimetry program was initiated in the 1980s. Dosimeters were collocated with air 

samplers. The current area dosimetry program was implemented in the mid-1990s to come into 

compliance with the DOE Radiological Control Manual requirements. Reports are issued and 

data was/is used for trending. If there is an increase in the trend, this may have been the result in 

additional radiological controls and external monitoring. The location of the earlier area 

dosimetry records is not known. 

Internal Dosimetry 

The internal monitoring during the TEC period of operations (1943-1947) included uranium 

urine tests and blood tests for uranium. From the 1950s onward, the plant had uranium urinalysis 

capabilities. Initially, internal monitoring for uranium was based on job evaluations, potential 

for uptake, and hands-on work with radioactive material. Air samples and bioassay trends were 

observed to evaluate potential updates to bioassay requirements for particular areas. The 

supervisor was responsible for notifying HP of job changes. 

Beginning in 2000, the RWP was used for determining bioassay requirements. For insoluble 

uranium (Buildings 9215 O-wing, 9215 M-wing, 9212 E-wing, 9201-5, 9201-5N, and machine 

shops), the frequency of the bioassay depends on the type of RWP an individual is working 

under. Each RWP had a bioassay indicator code to determine the type and frequency of samples. 

For example, an F RWP required the individual to submit paired urine and fecal samples 

bimonthly. With a Y RWP, the individual submits quarterly urine samples. This type of 

sampling was/is routinely evaluated to determine whether frequencies require adjustments. 
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Bioassay monitoring for radionuclides other than uranium has historically been based on the 

relative ratio of the particular radionuclide to the uranium. Y-12 implemented bioassay 

techniques for plutonium and other radionuclides at least as early as the 1980s. Prior to this, 

ORNL provided these bioassay services. 

Y-12 evaluated the potential dose from trace materials in recycled uranium. Although there was 

no significant dose contribution from incoming material (i.e., <10% of the internal dose), the 

raffinates were of concern as the trace materials were concentrated in this form. Neptunium-237 

was/is a primary contaminant in the raffinate stream. There are currently 2–3 site RWPs that 

required neptunium bioassay out of hundreds of RWPs issued. 

There was a set of Y-12 workers on loan to ORNL who worked on a plutonium project. ORNL 

provided plutonium and strontium analysis in the early to mid-1950s in support of this project. 

These results were provided to Y-12 for dose calculations and placed in the individual’s PDR 

file. 

Tritium monitoring was limited to a few individuals. Gas House (Heavy Water Conversion) 

personnel had been monitoring for tritium in the past. Tritium surveys were also performed in 

this area to track contamination. There were some areas, such as disassembly, where field 

instruments are used to monitor airborne tritium levels (e.g., Building 9204-2E). Field 

instruments monitoring for airborne tritium levels was discontinued and is no longer done. Site 

experts are not aware of the presence of tritides at the site. 

Since the mid-1990s, the worker monitoring (i.e., dosimetry and bioassay) has been based on the 

requirements of the RWP for the particulate area. Bioassay frequency is based on the solubility 

class of the radioactive material. It may also be required for a particular job. In general, the 

monitoring frequencies varied from monthly to annually. Site experts canvassed indicated that 

personnel monitoring criteria have changed over time. 

The criteria used to determine who was placed on what bioassay program also have varied over 

time. Lung counts were once performed on at least an annual basis. Additional lung counts 

were performed in the case of an incident. In-vivo counting was the chosen method for thorium 

monitoring. Fecal sampling was historically used as a special bioassay method, and was not 

performed routinely. There were hundreds of thousands of urine samples taken at Y-12 prior to 

the 1980s, as those individuals working directly with radioactive materials were on a weekly 

urine sample frequency. This can be demonstrated with a review of the data. 

Some support workers (e.g., janitors and maintenance workers) were not monitored via 

urinalysis or lung counts, even though they serviced and cleaned production areas in Buildings 

9206, 9212, and other areas of the plant. Some site experts noted that random urinalysis was 

performed in some of the shops before the 1980s. Many support workers did not recollect being 

put on a routine monitoring program and did not routinely submit samples prior to the 

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Currently, internal monitoring is specified in the RWP. Routine monitoring may include lung 

count, urinalysis, or fecal analysis. Fecal analysis was initiated in August 1998. The routine 

fecal sampling frequency at Y-12 is bi-monthly and is triggered based on RWPs. The worker is 

provided with a due date for the sample. When the RWP required a fecal sample, the worker 

received a card requesting the sample. The card may have been received a month after the job 

was completed. Since some fecal samples are not provided until weeks after the potential 

exposure, some workers question the meaningfulness of the sample. Health Physics has 

indicated that the sensitivity of the fecal sampling program has been evaluated and is well 

documented. There are fewer lung counts than in the past. In-vivo counts are based on a rolling 

12-month average of bioassay participants’ samples. Those with the highest average are counted 

first. Some individuals (e.g., janitors and security) no longer receive routine lung counts as they 

did in the past. They are not seen as key to production. Some production staff (e.g., chemical 

operators, casting workers, enriched uranium workers) who routinely work with radioactive 

materials are required to submit monthly urine samples and to have quarterly lung counts. Fecal 

sampling and lung counts are common for individuals working with Class Y uranium. 

During the process of plating parts with black uranium oxide (referred to as “black oxide”), 

“boiling” of the black oxide solution gave off considerable fumes. Currently, personal air 

monitors are used around black oxide operations in addition to fecal and urine bioassay. The 

shift to fecal and urine analysis from exclusively urine analysis occurred in 1998, when it was 

determined that urinalysis was insensitive to the insolubility of the high-fired oxides. Prior to 

1990s, if there was an incident, the worker got a lung count. In Building 9212 E-wing, 40–50 

workers were routinely exposed to high-fired (black) oxides. 

In the late 1950s, the Monday morning spot sampling technique was implemented for urine 

bioassay sampling. Workers were told to report to a sampling station after the weekend (any two 

consecutive days off) and leave a sample. In October 1989, the site switched to 24-hour 

sampling. Bioassay kits were taken home and brought back to work when completed, helping to 

minimize tampering and cross-contamination of samples. 

In-vivo counting was fairly accurate in measuring natural, depleted, and enriched uranium. 

Original counters were NaI detectors. The top five intakes at Y-12 were discovered via in-vivo 

counting due to the insolubility of the compound. In 1992, the site switched to germanium 

detectors. Information from in-vivo counting was provided to Internal Dosimetry for dose 

evaluation. 

With the use of well-water sampling, food study information, and a review of 238U 

concentrations in unexposed worker samples, a natural uranium background has been 

determined. Natural background uranium typically has a 234U to 238U ratio of 1:1. Enriched and 

depleted uranium have ratios of 3:1 and 0.9:1, respectively. For results above the detection limit, 

the ratio of 234U to 238U is evaluated. A ratio of greater than 1:1 is considered enriched uranium 

and a ratio of less than 1:1 is considered depleted uranium. This value is used in internal dose 

calculations. 
 

 

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Dose calculations at Y-12 were based on personnel monitoring data (i.e., urinalysis, fecal 

sampling, in-vivo counting). There are a few isolated cases where air monitoring was used to 

determine internal dose. Default internal dosimetry assumptions have changed over time. 

Inhalation was the default mode of intake. During 1989 to 1994, the default assumptions were 

“Q” Class material (90% Super-W/10%Y), 8 micron particle size, and a chronic exposure 

scenario. Class Q was a default assumption for select areas. The “Q” solubility class was 

originally discovered by early HP staff at Y-12. They observed an effective biological half-life 

in the lungs of 120 days. Class Super-W is a modification of Class W that increases the halftime in the lung from 50 to 120 days. The basis for the 8 micron particle size assumption was a 

particle size study completed in 9212 E-wing. The study indicated the average particle size was 

8 micron. There were also earlier particle size studies at the plant. From 1995 to 1997 during 

the plant standdown, an acute exposure with midpoint was assumed. In 1997, the default particle 

size was changed to 1 micron (i.e., ICRP default). In August 1998, the default assumptions were 

changed to solubility class based on work area. Both acute and chronic exposures were 

considered based on bioassay data. In 2000, the site issued an exemption request to 10 CFR 835, 

Occupational Radiation Protection, to allow the use of the Human Respiratory Tract Model for 

Radiation Protection (ICRP 66) lung model in internal dose calculations. The current Y-12 

internal dosimetry TBD provides information on potential missed dose based on derived 

investigation level intakes. 

The practice for closing out doses each year and reporting them to the DOE Radiation Exposure 

Monitoring System (REMS) repository was the responsibility of the facility that monitored the 

individual last. Several sites could calculate the dose during the year if an individual moved 

between sites, but only one site reported the individual’s dose. 

Historically, the areas with the greatest number of intakes were the chemical processing areas, 

Building 9212 E-wing operations, and casting. These individuals had more hands-on contact 

with radioactive material. Building 9215 M-wing tended to be a radiological “hot” area. 

In the past, internal dosimetry procedures were often documented in the HP reports. Dosimetry 

personnel determined the need for special bioassay sampling and work restrictions. Individuals 

were, in some cases, excluded from operations (given “cooling off” periods) when their wholebody count, urinalysis, or fecal analysis results exceeded a pre-established value. Currently, 

special bioassay samples for insoluble material generally include both urine and fecal samples. 

For fecal samples, one sample is taken right away and another a week later. For incidents 

involving soluble uranium, only urine samples are collected. Special sampling is done in the 

case of an incident (e.g., spill). 

There have been comparisons between various types of bioassay and field data at Y-12. For 

example, a comparison was done between urine data and air sampling data. The dose calculated 

based on urine data exceeded that calculated from air sampling data. 
 

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Air Sampling 

There have been fixed-head air samplers, breathing zone samplers, and continuous air monitors 

(CAMs) at Y-12. Y-12 had an extensive fixed-air head sampling program throughout the plant. 

The samplers were placed 6.2 feet above the ground. Air sampling placement has stayed 

consistent since at least 1969. In the 1960s, the air sampling equipment was modified to use 

punch cards with filters. The filters were mounted on the punch cards. During air sample 

exchange, the punch cards were simply exchanged, making the job more efficient. Whatman 41 

filters were primarily used for air sampling. In a few cases, Millipore samples were used for 

low-volume air sampling. Once the punch cards with filters were collected, they were merely 

fed through the counter. Each sampling location was assigned a specific code. The digits 

indicated the operation, department, and area within a department. Fixed-head air sample results 

were used to categorize airborne radioactivity areas, identify personnel protective equipment, 

provide first indication of potential intakes, and provide trending for air concentration levels. 

Currently, a concentration greater than 0.38 derived air concentration (DAC) requires the use of 

a respirator. 

There was limited testing of CAMs as early as 1992. CAM use was implemented relatively 

recently (in 1994). A small breathing zone (BZ) air sampling program was established in 1989 

for a period of 1 year. A full-fledged BZ air sampling program was established in 1998. There 

are currently between 20–30 CAMs used today. Along with the initiation of the BZ program, 

DAC-hour tracking was started. This data is used as a trigger to determine special bioassay 

(>20 DAC-hours) and appropriateness of respiratory protection. 

Flow meters, used in air sampling, were calibrated monthly, and typical flow rates are 

17 liters/minute. Air samples were counted initially and after a period of decay. There were 

areas with elevated levels of radon and thoron in the workplace; however, this was typically 

associated with background. There was no occupational dose calculation done for exposure to 

radon or thoron. Further information on radon and thoron concentrations can be obtained from a 

study that was completed by Y-12 Health Physics Services to evaluate radon and thoron 

concentrations in the workplace. 

There have been a few comparison studies between fixed-head air sampling and breathing zone 

sampling. One study indicated that the BZ results were 4–10 times higher, depending on the 

operation. A later study showed a difference of 10 or more, with the breathing zone sample 

being higher. 

Contamination Control 

The radiation protection program implemented and enforced at Y-12 prior to the mid-1980s was 

not as comprehensive as the current program. A number of issues existed prior to the mid-1980s, 

which would not be tolerated by today’s standards. 

• Gross contamination throughout plant areas 

• No Personal Protective Equipment (PPE) other than gloves 
 

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• No formal respiratory protection program 

• No As Low As Reasonably Achievable (ALARA) program 

• Eating, drinking, smoking permitted in highly contaminated areas 

• No radiation safety training (other than criticality) 

Management seemed to be more concerned about criticality safety and production, rather than 

radiation protection. In the areas where enriched uranium was handled, criticality safety was a 

significant concern. High Efficiency Particulate Air (HEPA) filters were watched carefully to 

ensure that concentrations did not create criticality safety issues. As a result of the concern for 

preventing criticality accidents, there were a number of analyses run by the safety department, 

even for simple operations. 

There was gross contamination in some areas of production. One janitor reported wearing a 

respirator just to sweep the steps in Building 9212 used by workers on their way to the local 

break room. Initially, respirators were not provided for this task. In general, contamination 

control for production workers prior to the mid- to late-1980s consisted of changing into 

coveralls and work shoes prior to entering operations areas; however, the change houses were 

not in the immediate operations area. Some workers were provided work gloves. When workers 

exited radiological areas, showers were taken and work clothes left behind. Although there were 

showers available, they were not required. Production workers were not concerned about taking 

contamination home. 

Managers, inspectors, and some support personnel (e.g., health physics technicians, security 

guards, engineering) wore their street clothes and shoes into radiation areas at the plant 

(sometimes with lab coats) and went home that way. Contamination control was such that 

material could be transferred home if personnel did not change their shoes. This was the case 

with support personnel who were not provided company shoes and who did not wear shoe 

covers. Periodically, personal vehicles were checked and sometimes found to contain 

contamination. 

The understood rule of thumb for Y-12 technicians was that “people were not surveyed.” The 

exceptions to this rule were when spills or accidents occurred. The first personnel contamination 

monitoring was done with portable alpha detectors, and was initiated in Building 9212 in about 

1989. When personnel contamination monitoring was first implemented, the instruments were 

put in the operating areas. The corrosive atmosphere of the operating areas caused instruments 

to fail. Health Physics eventually managed to move the personnel contamination monitors to the 

change houses. At this point, a clean side versus a potentially contaminated side was established. 

Finally, the equipment was moved near the production building exits. No egress monitoring 

(i.e., use of automated personal contamination monitors) was implemented at exit points of 

change rooms or main gates until the 1990s. PCM-1B and PCM-2s replaced manual frisking in 

the mid-1990s. In about 1989, the personnel contamination limit was 15,000 dpm/100 cm2 

alpha. In the early 1990s, this was eventually reduced to 5,000 dpm/100 cm2

 alpha. This 

contamination limit has been used since then. The transuranic areas have a lower contamination 

limit. 
 

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Beginning in the early 1990s, Y-12 began tracking entries into radiological areas. There were 

approximately 1,000,000 exits per year (multiple exits per person) from radiological areas. At 

times, radioactive material was tracked out of the immediate production area. 

Prior to 1990, it was common to eat, smoke, drink or chew gum in contaminated plant areas. For 

example, the Building 9204-4 lunch room was within 20 feet of a large metal press where 

depleted and highly enriched uranium were pressed. In Building 9215, the break room was on 

the other side of a sheet metal wall near an area handling enriched parts. Although there was an 

island in the production area for consuming food and drink, some employees kept their coffee 

and food in the immediate work area. Machinists were almost “chained” to their machines, in 

that they could not leave for even lunch or coffee breaks (even the restrooms were nearby). 

Security guards remember seeing visible black powder on food eaten by machinists. 

Management told workers not to worry about contamination and to take coffee back to their 

lathes and grinders. In fact, drinking large volumes of coffee and other liquids was said to be 

good for “cleaning out” soluble uranium. Managers insisted at the time that “uranium won’t hurt 

you.” The Building 9206 break room was closed a number of times due to elevated 

contamination. The Building 9206 change room had high contamination readings. In the 

Building 9215 break room, the seats had to be replaced because of fixed contamination. 

Individuals were not required to change and shower prior to entering break rooms or the 

cafeteria. In the late 1980s, individuals were directed to wash their hands prior to eating, and not 

to eat, drink or smoke in the production areas. 

The system developed for technical smears was similar to that used for air sampling. Cards were 

used in place of filter paper. A smear machine was developed to control the smeared area to 

100 cm2 . The cards were then counted. Some site experts indicated that prior to 1985, workers 

would accompany radiological technicians doing smear samples to measure removable 

contamination on equipment designated for outside sales. The workers would “acid wash” the 

location prior to the smear being taken. Others indicated that general areas were sometimes 

mopped prior to contamination surveys. 

Prior to modern posting requirements, Y-12 used two types of postings; (1) Regulated Area and 

(2) Contamination Control Zone. In Building 9201, radiation areas were roped off, but unbadged 

workers were still permitted to enter. New workers could observe activities in controlled areas 

and still not be badged unless they directly handled radioactive material. Personnel not handling 

radioactive material were not considered radiation workers subject to badging. Anybody who 

came onsite within the production areas could move freely about, even in street clothes. Even 

Building 9215 M-wing was not zoned and restricted until the 1970s. Health Physics personnel 

interviewed indicated that the criteria for personnel monitoring was/is well documented, and that 

non-radiation workers were badged. 

The engineering controls at Y-12 were established not only to protect workers from radiation, 

but also from chemicals. Engineering controls included hoods (sliding and open bay), 

gloveboxes, ventilation, and use of negative pressure. With the machining operations, each 

machine had an exhaust system and coolant was used on the material to reduce airborne 
 

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suspension. In the mid- to late-1980s, area monitors were installed on the production line 

machines. There was a lack of suitable engineering controls by today’s standards. 

High volume air sampling was performed in parts of plant; however, workers understood that 

when results came back with elevated readings, these were attributed to elevated “radon” from 

the bricks in the building. Air samplers were not operative at a number of interior plant building 

locations for considerable periods of time before the 1980s. 

A small BZ air monitoring program was implemented in 1989. Once a month, workers were 

selected in certain production areas to wear lapel air samplers for measuring BZ air 

concentrations. One worker remarked that it seemed to him that the BZ sampler was always 

given to the “cleanest” worker, i.e., the one with the least likelihood of high airborne readings, 

because elevated levels above certain criteria could shut a particular job down. A full-fledged 

BZ program was implemented in 1998. 

Little radiation work planning was conducted before the 1990s; “you just went where you needed 

to.” Also, no radiation protection training was provided. The RWP program began in 1995. 

From 1990 to 1995, there was a more casual RWP program. Work controls prior to 1990 were 

based on informal communications between HP and the production supervisors. Health Physics 

would notify production supervision about what personnel protective equipment (PPE), 

including respirators, were to be worn for a particular job. The supervisor was then to pass on 

these requirements to the workers performing the task. Maintenance activities were often done 

“off-shift” with little supervision and adherence to procedures. 

There are major differences in the level of PPE required historically versus currently. For 

example, in an area requiring no PPE in the past, full-face respirators, booties, and anticontamination clothing (anti C’s) are worn. ALARA was not implemented for uranium 

operations until the late-1980s. There was welding of highly enriched uranium metal 

components without respirators in Building 9206. Machinists handling thorium did not take any 

special precautions when grinding and shaping thorium metal. 

Workers had respirators in the mid- to late-1980s, but there were no requirements for their use 

during the Union Carbide tenure as operating contractor. At the discretion of the worker, they 

could carry respirators and don them if they felt conditions warranted additional protection. 

However, workers indicated that filter cartridges were often reused and stored in contaminated 

areas. Management would joke that “it was just a little dust; it will choke you first.” Each 

worker was assigned a single respirator. The individuals were responsible for cleaning them. 

Respirators were stored in an individual’s office or a cubicle. This was the practice until the 

mid-1980s. Following a DOE audit by headquarters, the site went to a single-use policy. Y-12 

was accused of using people as the controls by relying on bioassay limits. 

In Building 9206, before the 1970s or early 1980s, there were no scrubbers on the stacks or 

exhausts; highly radioactive dust and fumes were being released, and workers were being 

contaminated at high levels when they had to work on building roofs doing routine maintenance. 
 

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Plating ships in Buildings 9206 and 9212 would likely have had the “hottest” radiological 

releases. 

In September 1994, Y-12 was shut down because of violations with DOE safety requirements. 

This shutdown instigated major cultural changes in radiation protection practices at the plant. 

For example, eating, drinking, and smoking were finally prohibited in radiation areas. Another 

big change is that there are now formal operating procedures, as compared to the “seat-of-thepants” approaches followed before. On the downside, there were a lot of contamination 

incidents experienced following the 1998 shutdown. 

Radiation Generating Devices 

Radiation generating devices (RGDs) were commonly used at the Y-12 plant for nondestructive 

testing of weapons components. There were both stationary and portable units. Radiation 

generating devices used at Y-12 included a Van de Graff generator, a 14 Mev Linac, 60Co 

sources, a 252Cf source, electron beam welders, and x-ray units. These units were located in 

Buildings 9204-2E, 9203, 9204-4, 9201-5, 9980, and 9981. One 60Co source (5–7 Curies) was 

nicknamed the "casket." A bare 210Po source was received onsite at one point. An individual 

accidentally stepped on the source, causing a substantial spread of 210Po to the surrounding area. 

Incidents/Occurrences 

Incident reporting and documentation were not consistent through the years of operation at Y-12. 

Prior to the early-1990s, there was no formal process for documenting incidents as there is today. 

Line supervision was responsible for notifying Health Physics when an incident occurred. If an 

incident was significant, such as one resulting in significant personnel exposure, a summary 

report or correspondence was generated. The threshold for this type of incident reporting was a 

judgment call. The HP group also kept daily logs of radiological control activities. Items were 

provided to management as a part of a weekly report. These were consolidated into monthly and 

later quarterly reports. Monthly meetings were held and average air sample and survey results 

were discussed. These reports and meetings were also a mechanism for documenting incidents. 

For those incidents involving classified information, there is likely a classified and unclassified 

version of the report. The Radiological Records Center at Y-12 has incident reports and work 

restrictions by date going back to the 1950s. 

With the implementation of DOE occurrence reporting, a formal process was implemented. 

Currently, Radiological Control has an incident investigation procedure. Derived Air 

Concentration (DAC)-hour tracking, bioassay, and dosimetry are used as triggers for incidents. 

Personnel contamination > 5,000 dpm/100 cm2

 triggers a Personnel Contamination Report. 

Contamination > 50,000 dpm/100cm2 triggers occurrence reporting. An incident form is filled 

out by field radiological control staff. The field RadCon is responsible for determining who was 

involved and what occurred. Given this information and other field monitoring information, the 

internal dosimetry staff determines if special bioassay sampling is necessary. 
 

 

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There is a Dosimetry Investigation Database that allows for tracking and trending of incidents. 

The environmental group also maintains a database of spills. Currently, incident identification 

numbers are assigned to incidents with an extension for each individual involved. 

There were a number of major and minor incidents specifically mentioned by site experts: 

• Uranium chip fires 

• Elephant Snout (vacuum) rupture involving molten UF4. 

• Criticality accident 

• Process material spills and leaks 

Uranium metal “chip fires” were common in Building 9215 and in depleted and enriched 

uranium metal processing areas. The frequency was as high as 2–3 times per shift and would 

range from small flare-ups to large fires that would engulf machines. The final stage of HEU 

machining—fine machining—presented the largest fire hazard. Machinists were regularly 

exposed to uranium fire fumes and were expected to douse the fires themselves. Not all the 

uranium chip fires were formally documented. Health Physics would take a high-volume air 

sample after the fact. If the air count was high, there may have been a letter issued. 

In Building 9212 during the time period 1985–1993, Y-12 experienced “contained releases” of 

highly enriched uranium solutions in acid, which were cleaned up with mops wielded by 

workers. Leakage from interior process piping was common. During routine tours of Building 

9212 B-wing, guards reported seeing “green sludge” leaking from overhead pipes. Sometimes 

drip pans were used to collect leaking material. 

During the process for conversion to UF4, a torch was sometimes used to warm the fluid-beds. 

The fluid-beds had to be kept warm. The worker began using a torch to warm the bed. He 

stopped to take his lunch break. When he came back, he picked up the torch and began warming 

the fluid bed where he left off. Molten uranium sprayed all over the worker. He suffered acid 

burns, discoloration of his skin, and a substantial uptake of uranium. There was no personnel 

contamination monitoring until the Monday after the event. 

There was an incident with a machinist where the "elephant snout" became plugged with a wipe. 

Due to the plug in the system, containment failed. This incident is referred to as the Elephant 

Snout incident. 

Following the criticality accident in 1958, radiation monitoring was tightened considerably. 

Another era of tightened radiological practices was in 1985, when Union Carbide left as 

operating contractor. 

High-Risk Jobs 

There were several types of jobs that posed a higher risk to workers than others. High-risk jobs 

identified by RadCon include the following: 
 

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• Filter changes (internal) 

• Breaking containment for systems (internal) 

• Trap changes in the exhaust systems (internal) 

• Other maintenance activities 

• Reprocessing of material from the Savannah River Plant (external) 

• Uranium-233 storage (external) 

In general at Y-12, 75% of the dose came from internal exposure and 25% of the dose came from 

external exposure. 

Radiological Instruments 

Instrumentation used at the site has changed as new technology has become available. 

Beta/gamma survey instruments were used for the detection of depleted uranium (DU). Alpha 

survey instruments were used for the detection of enriched uranium (EU). The initial 

instruments used for radiation and contamination surveys at Y-12 were the following: 

• Sampson Nuclear Chicago Non-discriminating Ion Chamber (alpha survey) 

• Victoreen CDV-700 Thin Wall GM Detector (beta/gamma survey) 

• Cutie Pie (CP) Ion Chamber (dose rate) 

• Technical Associates Juno Discriminating Ion Chamber (alpha/beta/gamma) 

• Jordan Radector Gas-Filled Ion Chamber (Emergency Kit) 

• Teletector (Emergency Kit) 

• Tritium Monitor (Emergency Kit) 

• CP with gamma-to-neutron correction factor (neutron measurement). 

The Rem Ball was introduced in the late-1970s/early 1980s for work in the B-wing with green 

salt. Neutron surveys were conducted in areas handling enriched uranium (e.g., Buildings 9212, 

9215 M-wing, and 9215 O-wing). In the mid-1970s, the Ludlum Model 12 with air proportional 

probe and ZnS scintillation counters were introduced for alpha surveys. The CP was used 

through the late 1970s when it was replaced with the Eberline RO-2 and RO-5 ionization 

chambers. In the late-1970s/early 1980s, the Ludlum Model 3 with a pancake probe was 

introduced for beta/gamma surveys. Johnston tritium monitors were used in some areas for 

tritium detection. The current instruments used at Y-12 include the following: 

• Ludlum Model 12 Count Ratemeter with a Ludlum Model 43-5 

• Ludlum Model 12 Count Ratemeter with a Ludlum Model 43-65 (alpha) 

• Ludlum 2221 with Scalar Count Ratemeter with a Ludlum Model 43-65 (alpha) 

• 43-5 ZnS Scintillation Detector with alarm 

• Ludlum Model 3 survey meter with a Ludlum 44-9 (alpha/beta/gamma) 

• Eberline Model RO-2 ion chambers 

• Ludlum 2220 Scalar Ratemeter with Ludlum Model 43-65 (alpha) 

• RO-7 dose rate instrument (limited use) 

• RO-20 ionization chamber 
 

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• Bicron Model Micro Rem Tissue Equivalent Rate Meter 

• Ludlum Model 12-4 Count Ratemeter (Rem Ball) 

• Ludlum 177-45 Alarm Ratemeter with Ludlum Model 44-9 (alpha/beta/gamma detection) 

• Ludlum Model 177-45 Alarm Ratemeter with Ludlum Model 43-65 (alpha) 

• Eberline Model PCM-1B Personnel Contamination Monitor 

• Model PCM-2 Personnel Contamination Monitor 

• Ludlum Model 2929 Dual Scalar with a Ludlum Model 43-10-1 (alpha/beta) 

• Johnston Laboratories Triton Model III Tritium Air Monitor 

• Automess Model 6/12 Beta Teletechtor Dose Ratemeter 

• F & J Specialty Products Model HV- First High Volume Air Sampler 

• SAIC Model HD-28 Low Volume Air Sampler 

• Bicron Model Radiographer Dose Ratemeter 

• Eberline Model Alpha-6S CAM 

• Ludlum Model 239-1F Floor Monitor. 

The PCM-1B personnel monitor was introduced in about 1989. Early in the 1990s, the PCM-2 

was introduced. The Keithley Model 36100 Survey Meter was used after the CP was phased out, 

but is no longer in use. In the late-1980s/early 1990s, there was a substantial increase (i.e., 

approximately tenfold) in the number of radiation monitoring instruments onsite. 

Instrument calibration in the early years involved a single point calibration with an electroplated 

or planchet source. Y-12 implemented Radiation Protection Instrumentation Test and 

Calibration (ANSI N323 – 1978) in the mid-1990s. After implementation of ANSI N323 

(1978), a 60Co well source was used for ionization chamber calibrations. An infinite thickness 

uranium source (10” x 16”x 0.25”) was used to calibrate sidewall Geiger-Mueller counters. 

Infinite slab uranium sources are no longer used. Neutron instrumentation was/is performance 

checked using an AmBe source. 

Environmental Monitoring 

Prior to 1983, there were large ambient air samples collected from about 10–14 samplers within 

the perimeter. The filter media was large (10” x 14”). In addition to ambient air sampling, HP 

monitored stack releases, wells (core wells), groundwater, and biota. 

Depleted uranium was treated like any other metal. Billets were stored outside. At one point, 

RadCon observed a purplish trail leading from the DU stored outside and the drain. EU was 

more valuable and was stored in appropriate facilities. This material was more closely guarded. 

There were areas that handled residue where there were noticeable elevated levels of radon and 

thoron. 

Y-12 had two systems for environmental monitoring. The first system was maintained by ORNL 

for the Oak Ridge Operations (i.e., ORNL, Y-12, and K-25). Although ORNL managed the 

program, both Y-12 and K-25 supported this effort financially. The results from this monitoring 

program are documented in the Annual Site Environmental Reports (ASER). These reports have 

been issued since at least the 1980s. For the National Emission Standards for Hazardous Air 
 

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Pollutants (NESHAPS) reports, the releases are modeled by valley. Offsite ambient air monitors 

are used to validate the model. The Y-12 valley lies between Pine Ridge and Chestnut Ridge. 

Environmental data from this valley includes releases from ORNL operations located on the 

Y-12 site. Results are segregated by valley, because the meteorological conditions are specific to 

the valleys. The most representative air sample location is the one at the Scarboro Community. 

There is a good correlation between the NESHAPS-modeled Maximum Exposed Individual 

(MEI) and the air sample located at the Scarboro Community, with the modeling giving a higher 

dose. 

The second environmental monitoring system is in the perimeter air monitoring system. 

Originally, this system was managed by the Y-12 HP group. When the Environmental 

Monitoring (EM) group split from the HP group, this responsibility was transferred to EM. In 

1994, the number of onsite monitors in operation was reduced from 12 to 3. At this time, Y-12 

stopped operating the onsite system. There was no regulatory driver for operating these 

samplers, and the equipment did not meet current standards. The TDEC took control of three of 

the stations. Originally, the exchange rate was weekly, but TDEC changed this to bi-weekly. 

There has been an established soil, groundwater, and vegetation monitoring program at the site. 

Liquid effluent monitoring was/is permit driven. Data from liquid effluent monitoring are also 

available in the ASER. A state stream runs through the plant. As a result, there are monitoring 

points not far removed from the worker population. 

There was an extensive stack monitoring program. HEPA filters, scrubbers, and fiber filters 

were used to reduce air emissions. The NESHAPS reports list emission points at the site and 

associated controls at these emission points. Cyclones and baghouses have been less effective 

than HEPA filters. HEPA filters, which control environmental discharges or provide personnel 

protection, are tested every 18 months. There are also break-through monitors on major sources. 

The State of Tennessee is responsible for authorization of air permits at the Oak Ridge 

Operations, including Y-12. They have control over implementation of NESHAPS for the Oak 

Ridge area. The Environmental Protection Agency rules have been adopted by the State 

unchanged. The State also has Resource Conservation and Recovery Act control. As a result of 

the State relationship with Y-12, information on environmental monitoring may be available 

through the State. 

Both the NESHAPS report and ASER include routine and unplanned radiological releases. 

ORNL is responsible for compiling the ASER. The NESHAPS reports include information from 

multiple radionuclides. These reports are reservation-wide. 

Miscellaneous 

There were a number of unsanctioned practices that occasionally occurred related to the 

personnel monitoring program. Individuals would sometimes disassemble security badges to 

remove the criticality component, as it was made of precious metal. There is evidence that one 

individual was spiking his urine. The dosimetry folks were able to use air sampling data to 

determine that the urine results were false. This individual was fired. 
 

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As a result of the security at Y-12, all personnel and other records are screened prior to being 

provided to NIOSH. If there is a situation where the Mosaic Law applies, individual work 

history records may be sanitized. The dosimetry and medical records are left intact. There have 

been approximately 50 individual records sanitized prior to being provided to NIOSH. The 

Office of Worker Advocacy has reviewed the screening process for both Y-12 and K-25, and 

indicated that the process was appropriate. With respect to reports, much of the sanitizing has 

involved the removal of code words. 

NIOSH/ORAU did contact the internal and external dosimetry staff at Y-12 during the 

development of the Y-12 site profile. External dosimetry had several conversations with the 

ORAU team, and provided data retrieval support. Internal dosimetry also provided this support; 

however, they were actually asked to review and comment on the internal dosimetry site profile. 

In their latest visit to the site, HP and EM personnel were interviewed.